Method and apparatus for casting ingots

ABSTRACT

In an ingot mould, a hot top is formed of a lining of heatinsulating refractory material, and a plurality of metal plates located between the walls of the ingot mould and the lining, there being gaps between the mould wall and the lining at each corner, into which gaps the end of the metal plates extend, and into which molten metal flows during casting.

United States Patent Ageborg et al.

[451 Jan. 14, 1975 METHOD AND APPARATUS FOR CASTING moors Inventors: Ralf Ageborg; Jan Olof Beckman,

both of Aktiebolaget, Sweden Assignee: Foseco International Limited,

Birmingham, England Filed: Mar. 26, 1973 Appl. No.: 344,597

Foreign Application Priority Data Mar. 27, 1972 Norway 1042/72 US. Cl. .Q. 164/131, 249/106 Int. Cl B22d 7/10, B22d 29/00 Field of Search 249/106, 197; 164/131 References Cited UNITED STATES PATENTS 2/l 97l Kobusch et al. 249/106 X 3,752,435 8/1973 Daussan 249/l97 X Primary ExaminerRobert D. Baldwin Attorney, Agent, or FirmCushman, Darby & Cushman [57] ABSTRACT 8 Claims, 2 Drawing Figures PATENTEB JAN 1 41975 F IG].

METHOD AND APPARATUS FOR CASTING INGOTS The present invention relates to casting molten metal, particularly steel, to form ingots. When casting metals, particularly steel, in moulds, it is of great importance to be able to use the mould again as soon as possible after the casting is finished. It is thus desirable substantially to shorten the period of time the casting is in the mould. It is also desirable to reduce the period of time the casting is in the cooling bed.

Ingot moulds for steel casting are normally provided with a hot top disposed at the upper end of the mould or in a head box on the mould. The hot top is usually assembled from refractory heat-insulating components, for example, four plates for side surfaces and four wedges for the corners. The hot top may also be assembled from four plates and two wedges, or from four plates only.

The hot top remains in the mould until the steel has solidified, and the casting cannot be removed from the mould before this time since otherwise the hot top would then fall apart. This is due to its heat-insulating properties; the hot top keeps the metal in the hot top molten for sufficiently long that molten metal can refill the interior of the ingot as the steel, on solidifying, contracts.

According to the present invention, there is provided an ingot mould having a hot top formed of a lining of heat-insulating refractory material, and a plurality of metal plates located between the walls of the ingot mould and the lining, there being gaps between the mould wall and the lining at each corner, into which gaps the end of the metal plates extend, and into which, during casting, molten metal may flow.

Usually, steel plates are provided between the mould and the hot top, these steel plates extending over a substantial part of the height of the hot top and horizontally into the cavities provided in the corners of the mould. The plates may be solid or perforated or may be in the form of a mesh, e.g., a welded or expanded mesh.

The molten steel penetrates these cavities during casting and, in contact with the mould wall, the steel solidifies (in the corner portions) fairly rapidly and is joined to the ends of the steel plates. The hot top is then surrounded by a rigid steel frame formed shortly after pouring the casting has ended. This frame holds the components of the hot top together and, as soon as the outer layer of the casting has solidified and becomes self-supporting, the casting may be removed from the mould with the steel still molten in the hot top.

If necessary, a heat-conductive material can be provided on the top of the molten steel in the hot top so that here also a steel shell is quickly formed. In this manner, a steel casting is obtained which is still molten inside, but which is entirely surrounded by solidified material and which has a heat-insulating hot top even after the casting has been taken out of the mould. The casting can then be placed in a cooling bed for controlling the solidifying process.

The invention thus generally relates to a method of casting in a mould which, at its upper portion, is provided with a hot top of refractory material, and it is characterised in that, between the mould and the hot top on the sides thereof, metal plates are provided which terminate in spaced relationship from one another in the corner regions, and in that the molten metal cast in the mould is brought to flow into the corner regions of the mould to the height of the hot top in order to connect the opposing ends of the metal plates together on solidification.

The casting may be removed from the mould after solidification of the outer layers while the casting is still molten internally, and placed in the cooling bed.

In order to allow the steel to flow into the corner regions between the hot top and the mould, the hot top, at the corners thereof, may have a greater radius of curvature than the corner of the mould. The hot top may have, at the corners thereof, aperatures through which molten metal can flow.

In order to facilitate holding of the steel plates, the head box may be stepped on the sides facing toward the mould to support the steel plates.

The invention is illustrated, by way of example in the accompanying drawing, in which:

FIG. 1 is a vertical section through a mould with a hot top viewed from the side, and

FIG. 2 is a detail of the mould viewed from above and on a larger scale.

Referring to FIG. 1, part ofa mould l is shown in section. At the upper end of the mould, a hot top is formed by four plates 2 of refractory heat-insulating material, known per se, and four wedges 3 in the corners. The plates 2 have, at the top thereof, a projecting edge 4, so that they may be hung on the mould 1. In accordance with the invention, a steel plate 5 is disposed between the mould l and each of the plates 2, the steel plate 5 resting upon a step 6 at the lower edge of the plate 2. An aperture 7 is provided in each of the wedges 3.

A corner of a mould with a hot top in accordance with the invention is shown on a larger scale in FIG. 2. It may be seen here that the steel plates 5 project somewhat past the plates 2 and, due to the fact that the radius of curvature of the wedge 3 (indicated by the arrow 8) is greater than the radius of curvature of the corner of the mould 1 (indicated by arrow 9), there is a cavity 10 between the mould l and the wedge 3. During casting, molten steel flows up into the cavity 10 and fills this, filling being facilitated by means of the aperture 7 in wedge 3. The molten steel in the cavity 10 will substantially weld itself to the edges 11 of the steel plates 5 when it solidifies, and the solidification in the cavity 10 takes place much more rapidly than the solidification of the steel in the hot top. As soon as the outer layer of the rest of the casting, which is in contact with the cold mould, has hardened, the casting may be removed from the mould while the steel is still molten in the hot top since the hot top is now surrounded by a solid steel frame comprising the four steel plates 5 and the solidified steel in the cavities 10 between the mould l and the wedges 3 in the corners.

We claim:

1. An ingot mould having a hot top formed of a lining of heat-insulating refractory material, and a plurality of metal plates located between each of the side walls of the ingot mould and the lining, said lining being horizontally spaced from the corner walls to provide vertical gaps between the mould wall and the lining at each corner, adjacent ends of said metal plates extending into said corner gaps whereby during casting, molten metal may flow up into said gaps and substantially weld itself to said adjacent ends of said plates.

2. An ingot mould according to claim 1 wherein the lining has apertures in each corner to permit molten metal to flow into the gaps at the corners.

3. An ingot mould according to claim 1 wherein the outer radius of curvature of the lining at the corner of 5 the mould is greater than the radius of curvature of the inner surface of the mould corners.

4. An ingot mould according to claim 1 wherein the lining consists of four slabs and four corner wedges.

5. An ingot mould according to claim 1 wherein the surfacae of the lining adjacent the mould wall comprises a ledge on which the metal plates rest.

6. An ingot mould according to claim 1 wherein the plates are perforate.

7. In the method of casting a metal ingot, the improvement which comprises: pouring molten metal into an ingot mould having a hot top formed of a lining of heat-insulating refractory material, and a plurality of metal plates located between each of the side walls of the ingot mould and the lining, there being gaps between the mould wall and the lining at each corner, into which gaps the end of the metal plates extend, and into which, during casting, molten metal may flow; allowing the molten metal to penetrate into the gaps and there solidify and weld the plates together; and removing the part-solidified ingot from the mould while the metal in the hot top is still molten.

8. The method of claim 7 wherein a heat-conductive material is applied to the upper surface of the molten metal in the hot top thereby to cause the formation of a solidified upper crust. 

1. An ingot mould having a hot top formed of a lining of heatinsulating refractory material, and a plurality of metal plates located between each of the side walls of the ingot mould and the lining, said lining being horizontally spaced from the corner walls to provide vertical gaps between the mould wall and the lining at each corner, adjacent ends of said metal plates extending into said corner gaps whereby during casting, molten metal may flow up into said gaps and substantially weld itself to said adjacent ends of said plates.
 2. An ingot mould according to claim 1 wherein the lining has apertures in each corner to permit molten metal to flow into the gaps at the corners.
 3. An ingot mould according to claim 1 wherein the outer radius of curvature of the lining at the corner of the mould is greater than the radius of curvature of the inner surface of the mould corners.
 4. An ingot mould according to claim 1 wherein the lining consists of four slabs and four corner wedges.
 5. An ingot mould according to claim 1 wherein the surfacae of the lining adjacent the mould wall comprises a ledge on which the metal plates rest.
 6. An ingot mould according to claim 1 wherein the plates are perforate.
 7. In the method of casting a metal ingot, the improvement which comprises: pouring molten metal into an ingot mould having a hot top formed of a lining of heat-insulating refractory material, and a plurality of metal plates located between each of the side walls of the ingot mould and the lining, there being gaps between the mould wall and the lining at each corner, into which gaps the end of the metal plates extend, and into which, during casting, molten metal may flow; allowing the molten metal to penetrate into the gaps and there solidify and weld the plates together; and removing the part-solidified ingot from the mould while the metal in the hot top is still molten.
 8. The method of claim 7 wherein a heat-conductive material is applied to the upper surface of the molten metal in the hot top thereby to cause the formation of a solidified upper crust. 